To meet requirements of the 3rd Generation Partnership Project (The Third Generation Partnership Project, 3GPP for short hereinafter) communications system for a peak data rate and system bandwidth, carrier aggregation (Carrier Aggregation, CA for short hereinafter) is introduced into a 3GPP Long Term Evolution Advanced (Long Term Evolution Advanced, LTE-A for short hereinafter) system. For CA, larger bandwidth may be acquired by aggregating multiple contiguous or non-contiguous component carriers (Component Carrier, CC for short hereinafter). The CCs may be provided by a same base station, or may be provided by different base stations, where the former is referred to as intra-base station CA, and the latter is referred to as inter-base station CA. For inter-base station CA, multiple base stations provide multiple serving cells, and the multiple serving cells have an overlapping area. A base station may perform, according to specific wireless conditions and service statuses, carrier aggregation for user equipment (User Equipment, UE for short hereinafter) on serving cells that overlap. For inter-base station CA, a power headroom report (Power headroom report, PHR for short hereinafter) sent by the UE in any serving cell can be received only by a base station corresponding to the serving cell, and the base station that receives the PHR cannot learn an uplink resource allocation status of a serving cell provided by another base station. Consequently, in a same subframe, uplink resources allocated by base stations to the UE may fail to match an actual transmission capability of the UE, and therefore transmit power of the UE cannot be effectively controlled.